In coach vehicles such as busses, it is often desirable to feed ventilating or cooling air from the back of the coach section, where the engine is generally located, through a roof mounted plenum to the rest of the vehicle. This has advantages over feeding the air directly into the interior of the vehicle itself. This, however, presents problems when the coach vehicle is of the articulated type with a first vehicle section rotatably attached to a second vehicle section. The plenums in the vehicle must be connected and still allow the coach vehicle to articulate. An obvious solution is to connect the plenum in one section to the plenum in the other section by flexible conduits. This creates problems in that each conduit would require sufficient extra length to allow it to expand sufficiently as the coach vehicle articulates. Thus, the conduit on the opposite side would hang down obtrusively in the passenger space because of the required slack.